This invention relates to electroactive organic polymeric materials. More specifically, this invention relates to associating electroactivating agents known in the art as dopants with an organic polymer.
Recently, research has been conducted into organic polymeric materials in order to modify their room temperature electrical conductivity by reacting them with electron donor or acceptor molecules. The electron donor or acceptor molecules, generally known in the art as n- and p-type dopants respectively, can transform the organic polymeric materials so that these modified organic polymeric materials exhibit semiconducting and metallic room temperature electrical conductivity. Polyacetylene is an example of an organic polymeric material whose room temperature electrical conductivity can be modified over several orders of magnitude above its insulator state, by the incorporation of dopant molecules, A. J. Heeger et al, U.S. Pat. No. 4,222,903, said patent incorporated herein by reference. Other examples of organic polymeric materials whose room temperature electrical conductivity can be enhanced by several orders of magnitude over their insulator state by means of incorporation of dopant molecules are poly-p-phenylene, polypyrrole, poly-1,6 heptadiyne, and polyphenylene vinylene. However, all of the above recited examples are of organic polymeric materials which are completely insoluble or infusable and hence are completely intractable.
Other examples of organic polymers whose room temperature electrical conductivity can be modified with the aid of dopants are polyphenylene sulfide and poly-m-phenylene. However, the above recited materials though being tractable in their original virgin state, undergo irreversible chemistry when reacted with dopants which modify their room temperature electrical conductivity. This irreversible chemistry imparts upon these dopant modified organic polymeric materials a state of intractability. Upon removal of the doping agents, these materials do not revert to the chemical structure which they originally exhibited prior to being modified by the dopants. The inorganic material polysulfur nitride is also considered a polymeric conductor. As with the previously recited polymeric materials, polysulfur nitride is also completely intractable.
The synthesis of poly(1,3,4-oxadiazole-2,5-diylvinylene) and poly(1,3,4-oxadiazole-2,5-diyl-ethynylene) is described by I. Schopov et al. in Makromolecular Chemie, vol. 179, No. 1, pp. 63-71 (1978). These undoped oxadiazole polymers are shown by Schopov to exhibit an electrical conductivity characteristic of insulators.
U.S. Pat. No. 4,452,725 to Wellinghoff et al. describes an electrically conducting polymer obtained by doping poly(N-alkyl 3,3'-carbazolyl) with a compatible charge transfer acceptor.
For use in a wide variety of electronic device applications, it is highly desirable to have available organic polymeric electrically conducting materials having a preselected room temperature conductivity which can be varied over a broad range. This range should preferably extend from the insulator state of the unmodified organic polymeric material through the semiconducting regime and extending into the highly conducting metallic state. It is also desirable that these organic polymeric electrically conducting materials should be tractable and hence processable so that useful articles of any desired shape and size can be fabricated. Tractable organic polymers are those which can be readily shaped, formed, molded, pressed, cast, etc., into desired articles from the liquid state, i.e. either from the melt, fluid glassy state, or from solution after the completion of the polymerization reaction of the organic polymeric material.